I want marrows by the barrow-full…

How can I ensure the best yield from my marrows? Daniel Martin, London DAVID: In this heat, the most important thing for marrows and other cropping vegetables is a steady water supply. It will help stop marrows splitting.

Feed plants weekly with a high-potash liquid (such as tomato feed) to help them produce strong vegetables – and pick mature fruit regularly to keep the plant producing right through to October.